Novel dual-functional coating with underwater self-healing and anti-protein-fouling properties by combining two kinds of microcapsules and a zwitterionic copolymer

Abstract

Antibiofouling and repairing of the micro-cracked coating on the surface of the facilities in underwater environment are two great challenges in marine industries. This paper prepared a dual-functional coating with underwater self-healing and anti-protein-fouling properties by combining two kinds of microcapsules and a zwitterionic copolymer. First, epoxy resin microcapsules and underwater epoxy hardener microcapsules were prepared. Epoxy resin microcapsules with a poly(urea-formaldehyde) shell and the entrapped mixture of epoxy resin and n-butyl glycidyl ether showed homogeneous spherical morphology with encapsulation ratio of 90.42%. Underwater epoxy hardener microcapsules with a polymethyl methacrylate shell and the entrapped underwater epoxy hardener showed cellular spherical morphology with encapsulation ratio of 78.67%. Both of the microcapsules exhibited pretty thermal stability and acid, alkali and salt resistance. Then, two types of microcapsules were mixed with amine cured epoxy coating system to cast film on steel piece, and subsequently a zwitterionic polymer, ploy(sulfobetaine methacrylate-co-glycidyl methacrylate)(PSG) solution was casted on the surface of the un-cured epoxy coating. Therefore, a dual-functional coating with underwater self-healing and antibiofouling functions was obtained. The self-healing anticorrosion function attributed to the dual microcapsules and the anti-protein-fouling performance provided by PSG layer had been certificated. The facile combination of underwater self-healing and anti-protein-fouling functions may provide a new protection strategy for marine and other underwater facilities.